Iron Symbiote

You've stumbled upon a form of parasite made of liquid iron called an Iron Symbiote. It invades your body and influences you to sustain it with more iron. It forms a bond with you out of shared interest of survival. You gain certain unnatural abilities and can manipulate the parasite to your advantage in battle.

Iron Arm

Your iron symbiote functions as a shield, granting you + 2 to your Armor Class. You lose Proficiency with shields and are unable to benefit from using them. You also always have advantage on Athletics checks.

Assimilate Iron

Starting at 3rd level, your iron symbiote can absorb the iron from mundane items, tools or weapons. You can absorb 1 lb of iron this way using an Action. When you do so you gain an Iron Point. You can have a number of Iron Points equal to half your Class level (minimum 1) + your Constitution modifier. As long as you have at least one Iron Point, your Armor Class is 12 + Dexterity modifier and you are treated as wearing light armor and thus cannot benefit from any other armor. You also have resistance to Bludgeoning, Piercing and Slashing damage. 

At 7th level, as long as you have at least half of your attainable Iron Points, your Armor Class is 15 + Dexterity modifier (max 2) and you are treated as wearing medium armor.

At 10th level, as long as you have all of your attainable Iron Points, your Armor Class is 18, you are treated as wearing heavy armor and your speed is reduced by 10 feet.

At 14th level, as long as you have at least one Iron Point, your Armor Class is 18, you are treated as wearing heavy armor and your speed is reduced by 10 feet.

At 18th level, as long as you have at least half of your attainable Iron Points, your Armor Class is 20, you are treated as wearing heavy armor and your speed is reduced by 20 feet.

Outside of combat, whenever there is any form of mundane iron within 5 feet of you and you currently do not have full Iron Points, your iron symbiote will attempt to force you to assimilate it. You must make a Will save or be forced to assimilate it until your Iron Points are full. You are not able to assimilate iron off a moving creature or surface.

Blade Hand

When you attack, if you spend one Iron Point your iron symbiote can form natural weapons that you are considered proficient with. If you hit your target you deal 1d6 slashing damage + your Strength modifier. These attacks are not considered unarmed strikes. Before you make an attack with your Iron Symbiote, you can change the type of damage your attack will deal to bludgeoning, piercing, or slashing damage at will.

At level six your blade hand deals 1d8 + your Strength modifier as slashing, piercing or bludgeoning damage (your choice).

At level nine your blade hand deals 1d10 + your Strength modifier as slashing, piercing or bludgeoning damage (your choice).

At level twelve your blade hand deals 2d6 + your Strength modifier as slashing, piercing or bludgeoning damage (your choice).

At level fifteen your blade hand deals 2d8 + your Strength modifier as slashing, piercing or bludgeoning damage (your choice).

Survival Instinct

Starting at 7th level, when you are hit by an attack, you can expend an Iron Point and use your reaction to add your Constitution modifier to your armor class. If the attack would not hit, you do not suffer the effects of the attack.

Beast of Iron

Starting at 7th level, you manipulate the appearance of your Iron Symbiote to cause fear in your prey... enemy. If you bring a creature to 0 hit points while wearing the Iron Symbiote as armor, you can choose to target a single creature within 60 feet who can see you. The creature makes a Wisdom Saving throw. On a failed check they are frightened. The effect ends if the creature ends its turn out of line of sight of you or moves more than 120 feet away from you. If the creature succeeds on its saving throw, you can’t use this feature on that creature again for 24 hours. You have advantage on attacks against creatures that you have frightened.

Lights Out

At 10th level, when you succeed a Grapple against an enemy, if you have at least 1 Iron Point, you can take a Bonus Action to envelop the grappled foe's head with your Iron Symbiote. While their head is covered, if they require the eyes on their head to see then they are Blinded and if they require their head to breathe then they begin Suffocating. If they don't escape the grapple and end the suffocation in a number of rounds equal to their Constitution modifier they fall unconscious. While using this ability you have disadvantage on all attacks.

Iron Frenzy

At 15th level, you can now induce your iron symbiote to lash out at all your surrounding enemies. As long as you have at least half your maximum Iron Points, You can use your action to make a melee Attack against any number of creatures within reach of you up to your current total Iron Points, with just Attack roll for all targets. This attack expends one Iron Point per attack made this way. You are unable to use this ability again until you take a short or long rest.

Iron Vampire

At 18th level, you have learned how to use your abilities to directly siphon any iron from the biology of enemy creatures. When you hit a creature with your iron symbiote, you can force the target to make a Constitution saving throw against your Attack roll as the Dc. On a failed save they take necrotic damage equal to 4d12 + your class level, or half as much on a successful one. If the creature succeeds on its saving throw, you can’t use this feature on that creature again for 24 hours. If the target fails the saving throw, it becomes Exhausted. This effect remains until the effected creature takes a long rest. You regain hit points equal to half the damage you deal with this feature (rounded up) and you recover 4 Iron Points.